Author
Topic: Centrifuges Really Work (Read 4047 times)

I cold fuge my oils, granted they're WMO, slightly thinned with waste mineral turps, mainly fuge'ing to remove solids and water. The turps originates from a chainsaw wash bay, full of sand, metal filings, water, dust and goodness knows what. The WMO is from various backyard sources, mystery oil, gearbox, sump, diff, grease, dead kittens and puppies included.... This oil goes mostly to my burners these days, but I wouldn't hesitate to run it through the listers in an emergency...

Home made Hi-G fuge, single pass, low flow rate (its a tiny little fuge with the cup being less than 100dia and 100high...

The oils, on exit, are cold, the housing of the fuge barely warm... The air pressure in the fuge is slightly below atmospheric... During spinning of very wet oils and waterlogged diesel, I set the feed flow rate to just borderline water vapour expulsion.... This is not hot steam, but cold mist that emanates - I have some theories as to why, but no substantiated proof as such. At this flow rate, the spun product leaves the unit with little to no water content. But, it is a slow process... My targets for fuel production are but 3 to 4times my consumption... Meaning that I have a scaled down micro version that outputs about 10-20L per hour, depending on contaminant levels... (This is sludge we're talking about here...)

On polishing diesel or other liquids without heavy contamination, I could up the throughput substantially, as I have done in the past.... (Less than a 1% water/contamination level by volume)... The output product is significantly cleaner than store bought fresh diesel when viewed under a microscope.

As to energy usage - 100 to 150W, a little more when the scavenge pump kicks in, easily supplied by a small inverter/toy solar setup during daytime, load on a genset for night operation during emergency is more than tolerable as I use a VFD to control the fuge with soft start/stop... So, after a whole lot of rambling, NO, its not "heated steam" but a cold mist, keep the g's high enough and the flow within the limits of the cup, and you don't need to heat the input product either..... Well, not me, anyway.... But then I do everything arse backwards.... LOL....

In this scenario, the fuge is not eliminating the water, the added heat, presumably near the boiling point of water is. That is a lot of energy for even a 200L batch and if you are heating it electrically, a fairly slow and expensive process.

On a 20oC day at around 60% Humidity, I can dry and filter a 200L batch of oil in 30 min with well under .5 Kwh of power used with the bubbling/ pumping method.

Yes, the fuge is eliminating water. When you spin warm oil at 5000 g's at a very low flow rate (high retention time) the portion with the heavier specific gravity (water) is separated and pinned against the back ball of the centrifuge drum along with fats and particles. The clean oil continues on.

Define slow and expensive. My system draws 2.5 kw when running. For an 8 hour batch that's 20kw worth of power.At $0.08 per kwh that amounts to $1.60 per batch of 80 gallons (300 liters).

20Kwh, 8 hours, 300L?? Yep, nothing has changed. Still energy intensive, slow and expensive. Spose as long as we are happy with what we prefer, that's all that matters.

Hey Glort,I suppose if you consider $0.0053 per liter expensive then you would be correct.($1.60 per 300 liters)

You tried various methods and prefer settling. I tried various methods and settled on Spinning.Everyone has their own set of circumstances and constraints. Mine are very limited space and limited batch sizes.As long as it works, it really does not matter what system a person uses.

I suppose if you consider $0.0053 per liter expensive then you would be correct.($1.60 per 300 liters)

No, I don't consider the power cost expensive even though it would be 3 times greater here, just very energy intensive and wasteful. Spose it matters less now with people having solar but it was a big thing back in the heyday of veg. What I was meaning with expensive is the initial purchase setup cost. I see to buy a bowl type fuge is over $1600US atm. even the questionable little jet types arent cheap either...Not that they ever were and were made just down the road form me years ago.

Quote

As long as it works, it really does not matter what system a person uses.

Yes. The price is steep for the centrifuge setup. I have a few buddies who bought them.In my case I just bought the machined/balanced bowl and built the rest from scrounged metal.

I wonder how much longer WVO will be avialable in my area. 2 new companies have opened which set up free waste removal for restaurants. There we already several in operation. They process the VO on a large scale. Cleaning it for some use. I don't think it's for biodiesel because it's not economically feasible here. One by one restaurants are accepting their collection bin for waste oil dumping. Small VO collectors are running out of supply.These companies even pick up from private users. One of my friends had too much to process. He called them and they drove over with a vacuum truck and sucked WVO from two 1000 ltr IBC totes that he had.

Since the drop in Biodiesel interest there has not been much competition to get WVO. But with these new commercial processors, the remaining few home brewers are having trouble getting feedstock.

Seems people in some places have always had trouble getting oil and for others it's plentiful. Nothing new at all. In the veg heyday people were always complaining they couldn't get it but some of the approaches they used were pretty self explanatory why. The other thing is supply and these collection companies seem to come and go. Universally and world wide, they are always a bunch of immoral cowboys that make up their own rules and do what suits them.

Here some years back when they were after it for bio they went round threatening a lot of people using false EPA rules to get them to come on board and others they offered to pay. NO one ever got paid a cent and they didn't even collect for long before the price went down and they didn't bother collecting any more. This wasn't a small new company, this was some major waste companies still going today.

Oil was hard to get here but it took literally months for these twerps to burn a LOT of restaurateurs whom were then begging for someone to take the stuff away. It is no exaggeration to say I would go to some place to pick up and have two more owners coming out and asking if I would take their oil too. I doubled my collection setup from 2 to 400L and used to go out with a mate in his ute and collect 1000L in 2 Hours or less. One place had rows of drums and we used to pull up there and collect 1000L a week. That was a small shopping centre that had more restaurants than anything else. Geez they went through some oil in that place. That was the year I picked up 14,000L for my mate to make Bio with and for me to use as oil. I had 5000l+ in stock in the yard and a small shed full of oil. People that travelled on oil were always dropping in for a top up and I was like the WVO fuel station.

One of my best supplies was my brother in law whom worked for a waste company. They got a contract to take the used cooking oil off the cruise ships when they came in along with the rest of their rubbish. Each ship would have 2-4 IBC's full of Oil and it was bloody good, clean oil. Best I ever got! I'd go to his work with my trailer, he'd fork in a IBC and I was on my way. Sometimes i'd go home, pump it into my tanks and go back and get another. I could also drop one off to a mate, collect the empty and take that back and pick up a full one. There was always at least one waiting for me. No running round to various places pumping it, just loaded in an they must have cooked something ones and then changed the oil. It was like new and had very little moisture or particles so was a cinch to process. I sure miss that stuff!

Oil is still plentiful here. Generally it's put in open top 200L drums and I have a pump I made years ago I suck it out with into another 200L drum. Some companies have various styles of tanks but they are no problem. I doubt whether these new companies will survive. Seems to me that they come along, they make supply much more available which drives the price down and then they go out of business. Oil is used for a number of things, industrial lubricant, animal food or additive, used in some paints, sealants and rust preventative products and so on. I know of a couple of companies that use it for firing burners or Boilers for making cement and industrial heating. A large Potato chip company here burn their oil oil to cook the chips and rotate it that way.

The key as it has always been is to make alliances with the restaurants to get supplies. To them it is a waste product which is a liability and they want gone. If the stuff is there I collect it. Of course the do gooder purists have always had a sook about that. If came and took stuff out of their trash, particularly if it was over full or from their street cleanup, would they whine about that? Well, some probably would because the are never happy but as my restaurateur friend laughed, It's waste, we just want it gone, same as we want the rest of the rubbish gone and don't care who takes it as long as it disappears.

In the end I think oil supply is largely what one makes it. You can have plenty or none depending how much you really want it.